DB Autogrowth settings - Service Applications and content DBs

Hi - is there any documentation out there that provides specifics for the initial size and autogrowth settings for the SP2013 service application databases?

I'm aware that the content DBs will vary and thus impossible to define settings except to note that autogrowth needs to be set in MB not %. But for service app DBs surely there must be some guidelines on initial sizing?

Thanks

J